In order to control processes in process engineering, use is often made of known stored-program controllers (SPCs) which have been developed and constructed specially for this purpose. The strengths of such controllers are their particular suitability in terms of processing typical process control tasks such as, for example, collection of measurement data, logic linking, regulation and actuation of final controlling elements. For this purpose, various manufacturers have developed systems having a number of plug-in cards which are each specialized for specific functions.
A task which is to be processed specifically in software terms is then processed by way of a corresponding software program which is loaded into the stored-program controller.
For a long time, stored-program controllers were superior to what are referred to as universal computers (personal computers) in process engineering controllers, in particular with respect to processing speed and fail-safety.
The performance capability of such personal computers which are constructed from standard hardware is increasing at ever shorter time intervals. The performance advantages of stored-program controllers in process engineering control functions are thus becoming smaller and smaller.
Owing to the widespread distribution of personal computers, their standard hardware components and their favorable prices, it is desirable if software programs which have been developed for a stored-program controller can be executed on personal computers in order to make it possible to use the latter for process controllers.
A significant problem here is that the system requirements in terms of hardware and software of stored-program controllers and personal computers have basic differences so that, if a software program which has been developed for a stored-program controller is to be executed on a personal computer, it is usually necessary to completely redevelop a corresponding software program for the personal computer. Here, it is usually possible to use only the basic solution approach of the software program for the stored-program controller, but not reuse its specific program structure and implementation. Such a software program for the personal computer is therefore virtually a complete redevelopment which requires corresponding quality assurance.